| This Topic is part of Special Scientific Research Program funded for the Doctoral Program of Higher Education. Unabsorbable high molecular weight Antioxidants were researched to solved security problem of synthetic antioxidant. In this study, we adopts microcrystalline cellulose as carriers, using the unabsorbable characteristics of dietary fiber to creative design and first develop a series of antioxidant cellulose derivatives such as gallic acid cellulose ester, L-ascorbic acid cellulose ester,β-(3,5-tert butyl-4-hydroxyphenyl) propionate cellulose ester.The influence every factor on gallic acid cellulose ester, L-ascorbic acid cellulose ester,β-(3,5-tert butyl-4-hydroxyphenyl)pionate cellulose ester synthesis was studied. The supramolecular structure, chemical structure and structure of synthetic products were characterized by XRD,FTIR and SEM; The oxidation resistance was studied by scavenging superoxide anion radical, hydroxyl radical, alkyl radical and DPPH. The stability factors of products which were temperature, pH and ultraviolet irradiation. At last toxicological safety study, physical and chemical test of product was carried.Gallic acid cellulose ester were respectively synthesized firstly by direct esterification and indirect esterification. Taking esterification degreeas the final aim, optimum reaction conditions of direct esterification was that the ratio of gallic acid and microcrystalline cellulose ester was 4:1, catalyst was phosphotungstic acid, the amount of catalyst was 10% of Gallic acid, solvent was dioxane, temperature was 120℃, time was 10h. The esterification degree was more than 2.2. Indirect esterification adapted gall acetyl halogen and Hydroxy of microcrystalline cellulose to synthesize eater, the effect of which was better than esterification of Gallic acid and microcrystalline cellulose. The reaction was divided into four part. The optimum synthesis conditions of three acetyl gallic acid was obtained as follows:Add acetic anhydride to Gallic acid 1 g, pyridine was added in the in ice bath, it was sealed overnight, and put 2mol/L dilute sulfuric acid 17.50mL into this reaction, the yield was 92.10%; The optimum reaction time of tricetyl-galloylchloride was 3h with 25℃and then raising, temperature to 75℃. the yield reached 85% when the molar ratio of three acetyl gallic acid and thionyl chloride was 1:1.3. The synthesis conditions of three acetyl gallic acid cellulose ester was obtained as follows:the reaction temperature was 120℃, the reaction time was 1h, the molar ratio of microcrystalline cellulose and gallic acid cellulose ester was 1:4; And preparation conditions of gallic acid cellulose ester in a weakly alkaline medium were that the reaction temperature was 70℃and the reaction time was 1h. The results by IR showed that gallic acid cellulose was generated. The antioxidation effect of gallic acid cellulose ester embodied synthetically by multiple channels. On the one hand, massive phenolic hydroxyl in its phenolic hydroxyl offered hydrogen which had strong catching probability to free radical such as reactive oxygen species and so on, so it had inhibiting the production of free radical effect; On the other hand, it reduced catalysis which was that metal ions effected oxidation. The experimental results indicated that gallic acid cellulose ester can eliminate DPPH-free radical, superoxide anion radical, hydroxyl radical, alkyl radical. All kinds of free radical scavenging activity was lower than which of Vc, but higher than or approximate equal to the activity of gallic acid. For instance, compared with gallic acid, the eradication rate was less than 10% when the content was 5mg/mL. Secondly, products can eliminate superoxide anion free radical,which is gallic acid not possessed.Thirdly, hydroxyl free radical scavenging activity was reached to 50% of gallic acid., which is approached toVc. Fourthly, radical scavenging activity was higher than gallic acid obviously. The results of Stability test showed that gallic acid cellulose ester was storaged suitably under room temperature and it was good by high temperature sterilization and ultraviolet sterilization. The clearance rate of DPPH·was more stable with pH3.0-9.0. The acute toxinology experiment of gallic acid cellulose ester showed that it had no toxicity according to the acute toxicity (LD50>10.Og/kg). Compared with gallic acid(The safe dosage for mice was 5g/kg), the safety of propyl gallate which was used as food antioxidant (LD5o=862.2982mg/kg, hypodermic injection lethal dose was.4g/kg)was somewhat increased.L-ascorbic acid cellulose ester was synthesized firstly. The reaction was divided into two steps, preparation of carboxymethyl cellulose acyl chloride and synthesis of L-ascorbic acid cellulose ester. The optimum conditions of cellulose acetate showed from the results was that: DMF catalytic improved method was adopted, the ratio (W/V) of CMCH and SOCl2 was 1:3, the ratio (W/V) of CMCH and DMF was 1:20, the reaction temperature was 110-120℃, the reation time was 2h. The superior conditions was that:the ratio of solvent and L-ascorbic acid was 3.5:1, the ratio of carboxymethyl cellulose acyl chloride and L-ascorbic acid was 1:1.3, the reaction time was 22h, and the maximum conversion could reach 10%.The results of antioxidant experiment showed that antioxidation of L-ascorbic acid cellulose ester was inferior than which of Vc. But within the range of selected concentration,①The reducing power of L-ascorbic acid cellulose ester was very strong and the power increased with the increasing concentration. Both had good concentration-effect relationship.②The superoxide anion radical scavenging activity increased with the increasing concentration, which had good concentration-effect relationship.③The hydroxyl radical scavenging activity increased with the increasing concentration, which had conspicuous concentration-effect relationship.④The alkyl radical scavenging activity increased with the increasing concentration. The maximum was 74.10% when the concentration was 0.3-0.4 mg/mL.⑤L-ascorbic acid cellulose ester could significantly enhance activity of glutathione peroxidase.⑥L-ascorbic acid cellulose ester could inhibit lipid peroxidation and induced generation of final product MDA. It had conspicuous concentration-effect relationship.⑦L-ascorbic acid cellulose ester could inhibit organism oxidative damage and protect erythrocyte. The inhibition increased with the increasing concentration and which had conspicuous concentration-effect relationship. The results of stability experiment showed that the product stability was higher than Vc which was crystalline. The content of Vc was unchanged after heating for 2h under 70℃. The oxidation rate of product accelerated when reaction temperature was 70-90℃. The decomposition rate accelerated in the range of alkalinity and which was stable when the pH values was 2-7 in the range of neutrality and weak acidity. Ultraviolet radiation had no effect on product. Results of acute toxicity test showed LD50 of male and female mice was higher than 10.00g/kg·weight. It illustrated L-ascorbic acid cellulose ester was non-toxic level of materialβ-(3,5-tert butyl-4-Hydroxyphenyl) propionate cellulose ester was synthesized firstly. The optimum conditions was that catalyst was 4% absolute zinc acetate, the ratio of 3,5-methyl ester and microcrystalline cellulose was 2:1, temperature was 140℃, reaction time was 6h. The scavenging rate of P-(3,5-tert butyl-4-Hydroxyphenyl) propionate cellulose ester was much higher when the concentration was more than 3mg/mL. Alkyl radical scavenging rate of product was lower than 3,5-methyl ester obviously at high concentration, but which was 5% higher than 3,5-methyl ester when the concentration was lmg/mL. The acute toxinology experiment showed that P-(3,5-tert butyl-4-Hydroxyphenyl) propionate cellulose ester had no toxicity according to the acute toxicity (LD50>10.0g/kg). Compared with 1010 (LD5o>5g/kg)which was synthesized by 3,5-Methyl, the safety was somewhat increased.Synthetic products was detected according to several project of drying loss, burning crumbs(index was sulfate), arsenic(index was As), free phenol(index was p-cresol), heavy metal(index was Pb) and specific rotation. All the indexes of detection results met the requirement.In a word, synthetic products not only had antioxidant activity, but also had safe and nontoxic ability. And melting point of products were higher than before. It layed a foundation for prepared new functional polymer which had antioxidant activity.
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